Improved thermally controlled valve

Abstract: The present disclosure concerns an improved thermally controlled valve, to be installed in a cooling water system of internal combustion engines, etc., designed to eliminate thermal hunting by flowing the cooling water slightly at the initial stage of an increase in the cooling water temperature and flow more cooling water with further increase in the temperature by opening or closing passageways of the cooling water, comprising a valve element fastened to a moving unit of a thermo-element which works by detecting a change in the cooling water temperature and a valve seat which the valve element contacts with and separates from. The valve seat has a horizontal portion and a vertical portion which the valve element contacts with and separates from. The valve element is formed with a side in a convex shape and has a horizontal portion which contacts with and separates from the horizontal portion of the valve seat and a vertical portion which contacts with and separates from the vertical portion of the valve seat. A ring lip is formed on the vertical portion of the valve element, and the cooling water passageways are provided on the ring lip in a direction vertical to the ring lip.

Description: BACKGROUND OF THE INVENTION a) Field of the Invention The invention concerns an improvement of thermally controlled valves provided in cooling water systems for internal combustion engines, etc. and in particular, in a cooling water passageway between an engine and a radiator for opening or closing the passageway by contacting with or separating from a valve seat a valve element fastened to a moving unit moving by thermal expansion and shrinkage due to a change in temperature of the cooling water. b) Description of Prior Art Figure 1 shows an application example of a conventional unit of thermally controlled valve comprising a cylinder block 1 in which water jackets 2 are provided to circulate cooling water around each cylinder, a radiator 3 to air-cool the cooling water, cooling water passageways 4 1 and 4 2 linking the water jackets 2 with the radiator 3, and a water pump 5 provided near a return opening 2a of the water jackets 2 for the cooling water returning from the radiator 3 to the water jackets 2. The cooling water is circulated between the water jackets 2 and the radiator 3 by means of the water pump 5. A cooling water bypass 4 3 is provided between the cooling water passageways 4 1 and 4 2 . A thermally controlled valve TS is provided in a passageway between an engine on the outlet side of the cooling water in the water jacket 2 (on the inlet side of the cooling water in the radiator 3) for passing or shut-off the cooling water. Such a conventional unit of thermally controlled valve TS provided in the cooling water passageway is to open the valve element by opposing to the flow of the cooling water and hence the pressure of the cooling water ( vapor presure+discharge pressure of the water pump ) may give its influence on the opening or closing of the valve element and as a result, when the temperature of the cooling water reached a specified temperature set to open the thermally controlled valve, the valve element delays to open and opens at one stroke when the temperature exceeds the specified temperature to open the valve element. This phenomenon is called "overshoot" and the water cooled in the radiator flushes into the cooling water system to lower the temperature of the cooling water much below the temperature set to close the valve element and shut the valve element immediately. This phenomenon is called "undershoot". Repeating of the overshoot and undershoot generates a thermal hunting. Continued thermal hunting may cause instability in the cooling water temperature and causes problems as described hereunder. The cooling water having unstable temperatures entering the water jacket 2 of the engine reduces the service life of the engine or deteriorates the mileage due to the fluctuation of the temperature of the engine block or cylinder block. In addition, thermal control of air-conditioner is disordered and the driver may feel uncomfortable. Further, such an unstable temperature causes fluctuation of the reading of the water thermometer to give the driver anxiety. As shown in Figure 2, there is a conventional unit of thermally controlled valve TS' of vertical 2-stage to reduce the thermal hunting by preventing such a large amount of cold water from flowing at one stroke immediately after the opening of the valve and to hold down the initial flow rate. The thermally controlled valve TS' is comprised of a thermo-element TH, a case 6, a thermally expanding unit(wax) 7 for thermal expansion/shrinkage of a mixture of paraffin or cupper powder housed in the case 6, a diaphragm 8 made of nitrile rubber, etc. to seal the thermally expanding unit 7 in the case 6, a guide cylinder 9 connected with an opening of the case 6 through the diaphragm 8, and in succession from the diaphragm 8 in the guide cylinder 9 a fluid 10, a rubber piston 11, a back-up plate 12 made of poly-tetra fluoro-ethylene(P.T.F.E.), etc. and a moving unit 13 (piston). The thermally controlled valve TS' is comprised of a valve seat body 14, a support unit 15 mounted on the top thereof to which the moving unit 13 is pushed by a spring as described hereunder, a flange 14a of the valve seat body 14 fastened to the inner surface 17a of an elastic ring 17 formed with sealing projections 16 1 , 16 2 and 16 3 on the upper surface, lower surface and outer surface thereof. The elastic ring 17 is set into a housing, etc. in the passageway between the water jackets and the radiator to mount the thermally controlled valve TS'. The thermally controlled valve TS'is further comprised of a valve seat 14b formed near the flange 14a of the valve seat body 14, a valve element 18 the inner surface of which is slidably supported by the guide cylinder 9 forming the thermo-element TH, an outer surface 18a contacting with and separating from the valve seat 14b, a plurality of circulation holes 18b provided near the inner surface of the first valve element 18 and the bottom part 18c of the outer surface of the circulation holes 18b contacting with the top end 6a of the case 6. The second valve element 19 is a rigid pushing plate and the inner surface 19b is fastened to the guide cylinder 9 forming the thermally controlled valve TH so as to have the outer surface 19a face to a plan 18d (the upper side in the Figure) with a specified spacing and a circulation hole 19d is provided between the outer surface 19a and the inner surface 19b. The first spring 20 is mounted by compression between the pushing plate 19 and the first valve element 18. The second spring 21 is mounted on by compression between the first valve element 18 and a frame 22 fixed on the lower portion of a flange 14a of the valve seat body 14. A guide hole 22a is formed on lower portion of the frame 22 and the case 6 forming the thermally controlled valve TH is slidably supported by the guide hole 22a. A supporting axis 23 is connected with the bottom of the case 6 forming the thermally controlled valve TH and the third valve element 25 is slidably supported by a stopper 24 at the tip of the supporting axis 23. Third spring 26 is mounted by compression between the third valve element 25 and the case 6 forming the thermally controlled valve TH and the third valve element 25 is pushed by the third spring 26 to a valve seat 27 of the housing, etc. provided in a by-pass of the cooling water system. Because the vertical 2-stage thermally controlled valve is constructed as described above, when the temperature of the cooling water goes up, the thermally expanding unit 7 forming the thermally controlled valve TH expands, as shown in Figure 3(A), to project the moving unit 13 which is in contact with the supporting unit 15. However, the moving unit 13 does not move but the entire unit of the thermally controlled valve TH moves downward and the pushing plate 19 fastened to the guide cylinder 9 also moves downward to separate the tip 6a of the case 6 connected with the guide cylinder 9 from the bottom 18c of the valve element 18. Initially a small amount of cooling water flows as indicated by an arrow "a" through the spacing, the circulation hole 18b formed along the inner circumferential surface of the valve element 18 and circulation hole 19d formed on the pushing plate 19. When the temperature of the cooling water further goes up, the thermally expanding unit 7 forming the thermally controlled valve further expands as if the moving unit 13 projects from the guide cylinder 9 but to further lower the guide cylinder 9 and the case 6. Then, the outer circumferential surface 19a of the pushing plate 19 fastened to the guide cylinder 9 pushes the plane 18d of the valve element 18 downward to separate the outer circumferential surface 18a of the valve element 18 from the vlave seat 14b to flow the cooling water as indicated by an arrow "b" through the space between the valve seat 14b and the outer circumferential surface 18a of the valve element 18 and to flow as indicated by the arrow "a". As described above, a little amount of water is designed to flow initially with an increase in the temperature to prevent a large amount of cold water from flowing at one stroke when the valve is opened to restrain the initial flow to elimnate the thermal hunting. As shown in Figure 4 and Figure 5, there is another thermally controlled valve having a sub-valve to reduce such a thermal hunting. In the Figures shown hereunder, the structure identical to the thermally controlled valve of the vertical 2-stage type shall have identical identification marks. The units are comprised of a main valve TS 1 and a thermo-element TH 1 of a nearly equal construction to the conventional valve. The main valve TS 1 is mounted eccentrically from the center of the disk of the valve seat 14 (in the right hand). TS 2 is the sub-valve or a sub-thermally controlled valve and TH 2 is a thermo-element forming the sub-thermally controlled valve mounted eccentrically from the center of the disk of the valve seat 14(in the left hand in the Figure) and has nearly an identical structure to that of conventional units. The difference between the main thermally controlled valve TS 1 and the sub-thermally controlled valve TS 2 is described hereunder. Of the thermo-element TH 2 forming the sub-valve TS 2 , the tip end of the moving unit 13 is held eccentrically from the center of the valve seat body 14 by a holding unit 28. The guide cylinder 9 has a smaller diameter at an upper portion 9a and a larger diameter at a lower portion 9b. A circulation passageway 29 is formed between the upper portion 9a of the smaller diameter and the holding unit 28. The lower portion 9b is pushed to contact with a valve seat 30 passing through the circulation passageway 29 to close the valve by pushing up the lower portion of the sub-valve TH 2 by a spring-plate 31. The thermally controlled valve having a sub-valve is formed as described above and therefore, as shown in Figure 6(A), the thermally expanding unit 7 of the thermo-element TH 2 forming the sub-valve TS 2 expands with an increase in the water temperature. The moving unit 13 works to project but does not move because it is held by the holding unit 28 and the entire TH 2 moves downward and the guide cylinder 9 moves downward to have the lower portion 9b of the larger diameter separate from the valve seat 30. Then, the cooling water flows through the circulation passageway 29 as indicated by the arrow "a". Further, as shown in Figure 6(B), the thermally expanding unit 7 forming the thermo-element TH 1 expands with the increase in the water temperature to have the moving unit 13 work to project but the entire thermo-element TH 1 moves downward to separate the valve 18 fastened to the guide cylinder 9 resisting the spring 21 from the valve seat 14b. The cooling water flows as indicated by the arrow "b" through the spacing between the valve seat 14b and the valve element 18. The flow may be made as indicated by the arrow "a". As set forth above, the sub-valve is first opened with an increase in the temperature of cooling water to flow a small amount of water to the radiator and hence, a large amont of the cooling water is prevented from flowing at one stroke immediately after the opening of the valve. Thus, the initial flow is restrained and such a thermal hunting may be reduced. The thermally controlled valve of vertical 2-stage as shown in Figure 2 or the thermally controlled valve having a sub-valve as shown in Figure 4 and Figure 5 have the advantage of reducing thermal hunting. However, these conventional valves have to be assembled with many parts through various processes. In addition, the structures are fairly complex and therefore the production and the maintenance are costly. The weight is also heavier than that of thermally controlled valve having a single valve. Further, attention is drawn to JP-A-55 155 978 which shows an apparatus for opening and closing passages of seal valves separately in a thermostat for cooling water in an internal combustion engine by providing a plurality of seal valves in a valve to be operated by the thermal expansion of a wax element. Further, US-A-4 630 770 shows a valve construction having an annular valve seat and a movable valve member for opening and closing the valve seat and being operatively interconnected to a thermal power element that is carried by the valve construction. The valve member has an annular rigid part for engaging the valve seat and has an annular fexible part for also engaging the valve seat at a point upstream of the rigid part, the parts of the valve member being so constructed and arranged that the rigid part moves out of engagement with and away from the valve seat a certain distance before the flexible part moves out of engagement with the valve seat. The flexible part of the valve member has an opening therethrough that is adapted to provide a certain sized fluid path through the flexible part of the valve member when the rigid part of the valve member is engaging the valve seat. The present invention provides a thermally controlled valve as set forth in claim 1. Preferred embodiments are disclosed in the dependent claims. SUMMARY OF THE INVENTION The present invention relates to an improvement of the conventional units of thermally controlled valves by modifying the structure of the valves to streamline the construction and maintenance with eliminating the thermal hunting. DETAILED DESCRIPTION OF THE INVENTION The thermally controlled valve according to the present invention as shown in Figure 12, Figure 13 and Figure 14 is to be provided in a cooling water system for internal combustion engines, etc. to open or close the cooling water system. The thermally controlled valve is comprised of a valve element 18 fastened to a moving unit of thermo-element TH and a valve seat 14b. The valve seat 14b has a nearly horizontal portion 14b 1 and a nearly vertical portion 14b 2 which the valve element 18 contacts with and separates from . The valve element 18 is formed with a side in a convex shape and has a nearly horizontal portion 18e which contacts with and separates from the horizontal portion 14b 1 , a nearly vertical portion 18f which contacts with and separates from the vertical portion 14b 2 and two ring lips 18g 1 and 18g 2 formed on the vertical portion 18f. Small open cooling water passageways 18h 1 are provided on several parts (two parts in this case) of the first ring lip 18g 1 on the side of the horizontal portion 18e in a direction nearly vertical to the first ring lip 18g 1 . Large open cooling water passageways 18h 2 are provided on several parts of the second ring lip 18g 2 on the upper side of the vertical portion 18f in a direction nearly vertical to the second ring lip 18g 2 . Preferably the thermally controlled valve according to the present invention is formed with cooling water passageways 18h provided on several parts of one ring lip 18g formed on nearly vertical portion 18f of the valve element 18. The cooling water passageways 18h are formed in a direction nearly vertical to the ring lip 18g and in a tapered shape from the upper side of the valve element 18 toward the horizontal portion 18e. Preferably the thermally controlled valve according to the present invention is formed with cooling water passageways 18h 1 and 18h 2 provided on several parts (two parts in this case) of two ring lips 18g 1 and 18g 2 formed on a nearly vertical portion 18f of the valve element 18. The cooling water passageways 18h 1 and 18h 2 having a small open groove each are formed in a direction nearly vertical to the first ring lip 18g 1 on several parts (two parts in this case) in a tapered shape from the upper side of the valve element 18 toward the horizontal portion 18e and the cooling water passageways 18h 1 and 18h 2 having a large open groove each are formed in a direction nearly vertical to the second ring lip 18g 2 on several parts (two parts in this case) in a tapered shape from the upper side of the valve element 18 toward the horizontal portion 18e. Preferably the thermally controlled valve according to the present invention is to provide the thermo-element TH with a thermally expanding unit 7, which expands and shrinks with a change in the temperature of the cooling water, housed in a case 6 and has a moving unit 13 sliding a guide cylinder 9 connected with the case 6 by the thermally expanding unit 7 which thermally expands and shrinks and the tip end of the moving unit 13 is supported by the top end 14c' of a supporting portion 14c of the valve seat body 14 and the valve element 18 is fastened to the guide cylinder 9 moving reactively along with sliding of the moving unit 13 so as to contact with and separate from the valve seat 14b of the valve seat body 14. Of the thermally controlled valves according to the present invention (as shown in Figures 12, 13 and 14), the moving unit 13 is to project itself from the guide cylinder 9 by the expansion of the thermally expanding unit 7 due to an increase in the temperature of the cooling water. However, the tip end of the moving unit 13 is held with the top end 14c'of the supporting unit 14c of the valve seat body 14 and hence the moving unit 13 stays there and the entire thermo-element TH moves downward to move the valve element 18 fastened to the guide cylinder 9 . As a result, the horizontal portion 18e of the valve element 18 separates from the horizontal portion 14b 1 of the valve seat 14b. However, the ring lip 18g 1 formed on the vertical portion 18f still stays on the vertical portion 14b 2 and the cooling water flows slightly as shown by an arrow in Figure 10 (B) through the cooling water passageway 18h 1 formed in a direction nearly vertical to the ring lip 18 g 1 . When the temperature of the cooling water goes up further, the first ring lip 18g 1 formed on the vertical portion 18f separates from the vertical portion 14b 2 but the second ring lip 18g still stays on the vertical portion 14b 2 to flow the cooling water more as shown by an arrow in the Figure 10(C) through the cooling water passageway 18h 2 formed in a direction nearly vertical to the second ring lip 18g 2 . When the temperature of the cooling water goes up more, the second ring lip 18g 2 separates from the vertical portion 14b 2 and the cooling water flows further more as shown by an arrow in Figure 10 (D). BRIEF DESCRIPTION OF THE DRAWING Figure 1 is a drawing showing an application example of a conventional unit of thermally controlled valve. Figure 2 is a sectional drawing showing a valve element closed of a conventional unit of thermally controlled valve of vertical 2-stage. Figure 3 is a drawing showing the operation of a conventional unit of thermally controlled valve of vertical 2-stage. Figure 4 is a plane drawing showing a conventional unit of thermally controlled valve having a sub-valve. Figure 5 is a sectional drawing showing a valve element closed of a conventional unit of thermally controlled valve having a sub-valve. Figure 6 is a drawing showing the operation of a conventional unit of thermally controlled valve having a sub-valve. Figure 7 is a sectional drawing showing a valve element closed of the thermally controlled valve not part of the present invention. Figure 8 is an enlarged drawing showing a valve element and a valve seat closed of the thermally controlled valve not part of the present invention. Figure 9 is a drawing showing the operation of the thermally controlled valve not part of the present invention. Figure 10 is a drawing showing the structure of the major valve element and valve seat and the operation of the thermally controlled valve not part of the present invention. Figure 11 is a drawing showing detailed structure of a valve element of the thermally controlled valve not part of the present invention. Figure 12 is a drawing showing an example of the thermally controlled valve according to the present invention. Figure 13 is a drawing showing other example of the thermally controlled valve according to the present invention. Figure 14 is a drawing showing other example of the thermally controlled valve according to the present invention. Figure 17 is a drawing showing a graph of flow rate properties of the thermally controlled valve according to the present invention as compared with those of a conventional unit of thermally controlled valve. DESCRIPTION OF THE PREFERRED EMBODIMENT The preferred embodiments of this invention are described hereunder with reference to the accompanying drawings. The detailed difference between the thermally controlled valve according to the present invention and the conventional units of thermally controlled valves is described hereunder. Figure 8 shows a detail of the valve seat 14b of the thermally controlled valve TS which is not claimed in the present invention, formed on the valve seat body 14, having a nearly horizontal portion 14b 1 and a nearly vertical portion 14b 2 . The difference between this thermally controlled valve TS and the conventional units is that the valve element 18, which contacts with and separates from the valve seat 14b, is formed with a side in a convex shape, the horizontal portion 18e which contacts with and separates from the horizontal portion 14b 1 , the vertical portion 18f which contacts with and separates from the vertical portion 14b 2 and a ring lip 18g formed on the nearly vertical portion 18f and the cooling water passageways 18h formed on several parts of the ring lip 18g with a groove in V-shape each tapered from the upper side of the valve element 18 toward the horizontal part 18e in a direction nearly vertical to the ring lip 18g. The cooling water passageways 18h are formed as described above and therefore as shown in Figure 9(A) the moving unit 13 is to project itself with expansion of the thermally expanding unit 7 due to an increase in the temperature of the cooling water. However, the tip end of the moving unit 13 is held with the top end 14c'of the supporting unit 14c of the valve seat body 14. Hence, the moving unit 13 stays there and the entire thermo-element TH moves downward to move the valve element 18 fastened to the guide cylinder 9 and as a result, the horizontal portion 18e of the valve element 18 separates from the horizontal portion 14b 1 of the valve seat 14b. However, the ring lip 18g 1 formed on the vertical portion 18f still stays on the vertical portion 14b 2 and the cooling water flows slightly as shown by an arrow "a" through the cooling water passageway 18h (as shown in Figure 8) formed in a direction nearly vertical to the ring lip 18 g 1 . When the temperature of the cooling water goes up further, as shown in Figure 9(B), the valve element 18 fastened to the guide cylinder 9 moves more downward to have the ring lip 18g formed on the vertical portion 18f separate from the vertical portion 14b 2 and the cooling water flows more as shown by an arrow "b" as in the case of the conventional units. When the temperature of the cooling water goes up more, the second ring lip 18g 2 separates from the vertical portion 14b 2 and the cooling water flows more as shown by an arrow in Figure 10 (D). Figure 10 shows the major portion of a thermally controlled valve which is not part of this invention and the operation of the valve element and the valve seat. The thermally controlled valve is provided in a cooling water system for internal combustion engine, etc. to open or close the cooling water system and is comprised of the valve element 18 fastened to the moving unit of the thermo-element TH which works by detecting the temperature of the cooling water and a valve seat 14b which the valve element 18 contacts with and separates from. The valve seat 14b has a nearly horizontal portion 14b 1 which the valve element 18 contacts with and separates from and a nearly vertical portion 14b 2 . The valve element 18 has a side formed in a convex shape and has a nearly horizontal portion 18e which contacts with and separates from the horizontal portion 14b 1 , a nearly vertical portion 18f which contacts with and separates from the vertical portion 14b 2 and two ring lips 18g 1 and 18g 2 formed on vertical portion 18f. Passageways 18h 1 and 18h 2 are provided on several parts ( two parts in this case ) of the two ring lips 18g 1 and 18g 2 in a direction nearly vertical to the two ring lips 18g 1 and 18g 2 . The operation of the thermally controlled valve is as shown in Figure 10(A). When the temperature of the cooling water is low, the horizontal portion 18e contacts with the horizontal portion 14b 1 in the closing condition. When the temperature of cooling water goes up to expand the thermally expanding unit 7, the moving unit 13 is to project itself. However, the tip end of the moving unit 13 is held at the top end 14c'of the supporting unit 14c of the valve seat body 14 . Hence, the moving unit 13 stays there and the entire thermo-element TH moves downward to move the valve element 18 fastened to the guide cylinder 9 and as a result the horizontal portion 18e of the valve element 18 separates from the horizontal portion 14b 1 of the valve seat 14b (see Figure 10(B)). However, the first ring lip 18g 1 formed on the vertical portion 18f still stays on the vertical portion 14b 2 and the cooling water flows slightly as shown by an arrow through the cooling water passageway 18h formed in a direction nearly vertical to the rig lip 18 g 1 . When the temperature of the cooling water goes up further, as shown in Figure 9(B), the valve element 18 fastened to the guide cylinder 9 moves more downward to have the ring lip 18g formed on the vertical portion 18f separate from the vertical portion 14b 2 and the cooling water flows more as shown by an arrow "b" as in the case of the conventional units. When the temperature of the cooling water goes up further more, the second ring lip 18g 2 separates from the vertical portion 14b 2 to flow more cooling water as shown by an arrow in Figure 10 (D). Figure 11 shows the detail of the valve element 18. Passageways 18h 1 and 18h 2 are provided on several parts (two parts in this case) of the two ring lips 18g 1 and 18g 2 formed on the vertical portion 8f of the valve element 18 in a direction nearly vertical to the two ring lips 18g 1 and 18g 2 . The cooling water passageways 18h 1 and 18h 2 having a small open groove each are formed in a direction nearly vertical to the first ring lip 18g 1 on several parts (two parts in this case) of the first ring lip 18g 1 in a tapered shape from the top end of the valve element 18 toward the horizontal portion 18e. Further, the cooling water passageways 18h 1 and 18h 2 having a large open groove each are formed in a direction vertical to the second ring lip 18g 2 in a tapered shape from the top end of the valve 18 toward the horizontal portion 18e. The small open groove and the large open groove forming the cooling water passageways 18h 1 and 18h 2 are in a v-shape and the groove bottoms b 1 and b 2 are sloped downward. The cooling water passageways 18h 1 and 18h 2 are formed as described above and therefore the cooling water flow increases at a specified gradient of flow rate with the separation of the two ring lips 18g 1 and 18g 2 from the vertical portion 14b 2 . Of Figure 17, the axis of ordinate indicates the logarithmic properties of cooling water flow rate X of a conventional unit of thermally controlled valve, of flow rate Y of the thermally controlled valve having one ring lip 18g on the valve element 18 and of flow rate Z of the thermally controlled valve having two ring lips 18g 1 and 18g 2 on the valve element 18 according to the present invention. The axis of abscissa indicates the spacing between the valve element and the valve seat. In the case of the flow rate X of the conventional unit of thermally controlled valve, the flow rate increases at a fixed flow rate gradient proportional to the spacing between the valve element and the valve seat. In the case of the flow rate Y of the thermally controlled valve in which one ring lip 18g is provided on the valve element 18 and the cooling water passageway 18h is provided on the ring lip 18g, the flow rate of the cooling water flowing through the cooling water passageway 18h is low until the time( Y 1 ) the ring lip 18g separates from the vertical portion 14b 2 . When ( Y 2 ) the ring lip 18g separates from the vertical portion 14b 2 , the flow rate increases in proportion to the spacing between the valve element and the valve seat. The gradient ( Y 1 ) of the flow rate of the cooling water flowing the cooling water passageway 18h may be designed at a desired value by adjusing the size of the open groove in a V-shape and the slope of the groove bottom forming the cooling water passageway 18h, etc. In the case of the flow rate Z of the thermally controlled valve according to the present invention in which two ring lips 18g 1 and 18g 2 are provided on the vertical portion 18f and the cooling water passageways 18h 1 and 18h 2 are provided on the ring lips 18g 1 and 18g 2 , the flow rate is low until the time ( Z 1 ) the first ring lip 18g 1 separates from the vertical portion 14b 2 . The flow rate is more than that in the case of Z 1 until the time ( Z 2 ) the second ring lip 18g 2 separates from the vertical portion 14b 2 . When( Z 3 ) the second ring lip 18g 2 separates from the vertical portion 14b 2 . the flow rate increases more. Other embodiments of the thermally controlled valve according to the present invention shown in Figure 12( A ) and ( B ), Figure 13( A ) and Figure 14( A ) and ( B ) indicate two ring lips 18g 1 and 18g 2 formed on the vertical portion 18f and the cooling water passageways 18h 1 and 18h 2 formed on the ring lips 18g 1 and 18g 2 . Each (A) in the Figures is a plane drawing viewing the valve element 18 from the lower side and each (B) is a side elevation of the cooling water passageway. The valve element 18 is formed with the side in a convex shape and has a nearly horizontal portion 18e which contacts with and separates from the horizontal portion 14b 1 and a nearly vertical portion 18f which contacts with and separates from the vertical portion 14b 2 and the two ring lips 18g 1 and 18g 2 formed on the vertical portion 18f. Small open cooling water passageways 18h 1 are provided on several parts (two parts in this case) of the first ring lip 18g 1 on the horizontal portion 18e in a direction vertical to the first ring lip 18g 1 . Large open cooling water passageways 18h 2 are provided on several parts of the second ring lip 18g 2 on the vertical portion 18f in a direction nearly vertical to the second ring lip 18g 2 . The flow rate properties and the gradient of the flow rate, etc. as shown by (Z 1 ) and (Z 2 ) in Figure 17 may be changed as required by adjusting the design of the size or shape or groove bottom slope of the small open cooling water passageways 18h 1 or the large open cooling water passageways 18h 2 respectively. As described above, upon an increase in the temperature of the cooling water, the valve opens to flow initially a little cooling water to the radiator and when the temperature goes up, the valve opens more widely to flow more cooling water. In this way, a large amount of the cooling water is prevented from flowing at one stroke immediately after opening of the valve. Thus, the initial flow is restrained and such a thermal hunting can be eliminated. The thermally controlled valve according to the present invention is to improve the valve element or the valve seat to flow a little cooling water initially to the radiator upon an increase in the temperature of the cooling water and to prevent a large amount of the cooling water from flowing at a stroke as in the case of the conventional units of thermally controlled valves of a vertical 2-stage type or having a sub-valve. In addition, various thermally controlled valves having optimum flow rate properties are available by designing the most suitable position and shape of the ring lips formed on the vertical portion of the valve element, number and size of the cooling water passageways formed on the ring lips and spacing between the vertical portions of the valve element and the valve seat of particular models of automobiles, It is noteworthy to describe that the improvement may be made on the valve element and the valve seat only and therefore the thermally controlled valve according to the present inventon can be assembled with less number of parts through less assemblying processes as compared with the conventional thermally controlled valves of vertical 2-stage or having a sub-valve. As a result, the thermally controlled valve of this invention requires less production and less maintenance costs that are almost equal to those costs of the Conventional general single valves.

Claims: A thermally controlled valve, to be provided in a cooling water system for internal combustion engines, to open or close passageways of the cooling water, comprising a valve element (18) fastened to a moving unit of a thermo-element (TH) and a valve seat (14b) which the valve element (18) contacts with and separates from,and the valve seat (14b) has a nearly horizontal portion (14b 1 ) and a nearly vertical portion (14b 2 ) which the valve element (18) contacts with and separates from, and the valve element (18) is formed with a side in a convex shape and has a nearly horizontal portion (18e) which contacts with and separates from the horizontal portion (14b 1 ) of the valve seat (14b) and a nearly vertical portion (18f) which contacts with and separates from the vertical portion (14b 2 ) of the valve seat (14b), characterised in that two ring lips (18g 1 , 18g 2 ) are formed on the vertical portion (18f) of the valve element (18), and small open cooling water passageways (18h 1 ) are provided on several parts of the first ring lip (18g 1 ) on the side of the horizontal portion (18e) of the valve element (18) in a direction nearly vertical to the first ring lip (18g 1 ) and large open cooling water passageways (18h 2 ) are provided on several parts of the second ring lip (18g 2 ) on the upper side of the vertical portion (18f) of the valve element (18) in a direction nearly vertical to the second ring lip (18g 2 ). The thermally controlled valve according to claim 1, wherein the cooling water passageways (18h 1 , 18h 2 ) provided on several parts of one ring lip (18g 1 , 18g 2 ) formed on the nearly vertical portion (18f) of the valve element (18) in a direction nearly vertical to the ring lip (18g 1 , 18g 2 ) are provided with an open groove each in a tapered shape from the upper side of the valve element (18) toward the horizontal portion (18e) of the valve element. The thermally controlled valve according to claim 1, wherein the cooling water passageways (18h 1 , 18h 2 ) provided on several parts of two ring lips (18g 1 , 18g 2 ) formed on the nearly vertical portion (18f) of the valve element (18) are formed with a small open groove each formed on several parts of the first ring lip (18g 1 ) in a direction vertical to the first ring lip (18g 1 ) and in a tapered shape from the top end of the valve element (18) toward the horizontal portion (18e) and a large open groove each formed on several parts of the second ring lip (18g 2 ) in a direction vertical to the second ring lip (18g 2 ) and in a tapered shape from the upper side of the valve element (18) toward the horizontal portion (18e) of the valve element (18). The thermally controlled valve according to claim 1, wherein the thermo-element (TH) is provided with a thermally expanding unit (7), which expands and shrinks with a change in the temperature of the cooling water, housed in a case (6) and has a moving unit (13) sliding a guide cylinder (9) connected with the case (6) by the thermally expanding unit (7) which thermally expands and shrinks, and the tip end of the moving unit (13) is supported by the top end (14c') of a supporting portion (14c) of the valve seat body (14), and the valve element (18) is fastened to the guide cylinder (9) moving reactively with sliding of the moving unit (13) so as to contact with and separate from the valve seat (14b) of the valve seat body (14).

Inventors: HAMANO MASAHISA, HOMMA HITOSHI, KAI KAZUYUKI, MASUKO TAKASHI, MORI AKIRA, HAMANO, MASAHISA, HOMMA, HITOSHI, KAI, KAZUYUKI, MASUKO, TAKASHI, MORI, AKIRA
Applicants: NIPPON THERMOSTAT KK, NIPPON THERMOSTAT CO., LTD.
Application year: 1994
Main classification: G05D23
IPC codes: F16K31, G05D23, F01P7